patch 8.1.1055: CTRL-G U in Insert mode doesn't work for shift-Left

Problem:    CTRL-G U in Insert mode doesn't work to avoid splitting the undo
            sequence for shift-left and shift-right.
Solution:   Also check dont_sync_undo for shifted cursor keys. (Christian
            Brabandt)

src/edit.c

@@ -236,11 +236,11 @@ static void ins_mousescroll(int dir);
 #if defined(FEAT_GUI_TABLINE) || defined(PROTO)
 static void ins_tabline(int c);
 #endif
-static void ins_left(int end_change);
+static void ins_left(void);
 static void ins_home(int c);
 static void ins_end(int c);
 static void ins_s_left(void);
-static void ins_right(int end_change);
+static void ins_right(void);
 static void ins_s_right(void);
 static void ins_up(int startcol);
 static void ins_pageup(void);
@@ -290,10 +290,10 @@ static int	ins_need_undo;		/* call u_save() before inserting a
 					   char.  Set when edit() is called.
 					   after that arrow_used is used. */
 
-static int	did_add_space = FALSE;	/* auto_format() added an extra space
+static int	did_add_space = FALSE;	// auto_format() added an extra space
-					   under the cursor */
+					// under the cursor
-static int	dont_sync_undo = FALSE;	/* CTRL-G U prevents syncing undo for
+static int	dont_sync_undo = FALSE;	// CTRL-G U prevents syncing undo for
-					   the next left/right cursor */
+					// the next left/right cursor key
 
 /*
  * edit(): Start inserting text.
@@ -1284,7 +1284,7 @@ doESCkey:
 	    if (mod_mask & (MOD_MASK_SHIFT|MOD_MASK_CTRL))
 		ins_s_left();
 	    else
-		ins_left(dont_sync_undo == FALSE);
+		ins_left();
 	    break;
 
 	case K_S_LEFT:	/* <S-Left> */
@@ -1296,7 +1296,7 @@ doESCkey:
 	    if (mod_mask & (MOD_MASK_SHIFT|MOD_MASK_CTRL))
 		ins_s_right();
 	    else
-		ins_right(dont_sync_undo == FALSE);
+		ins_right();
 	    break;
 
 	case K_S_RIGHT:	/* <S-Right> */
@@ -9291,10 +9291,10 @@ ins_horscroll(void)
 #endif
 
     static void
-ins_left(
+ins_left(void)
-    int	    end_change) /* end undoable change */
 {
     pos_T	tpos;
+    int		end_change = dont_sync_undo == FALSE; // end undoable change
 
 #ifdef FEAT_FOLDING
     if ((fdo_flags & FDO_HOR) && KeyTyped)
@@ -9378,8 +9378,9 @@ ins_end(int c)
 }
 
     static void
-ins_s_left(void)
+ins_s_left()
 {
+    int end_change = dont_sync_undo == FALSE; // end undoable change
 #ifdef FEAT_FOLDING
     if ((fdo_flags & FDO_HOR) && KeyTyped)
 	foldOpenCursor();
@@ -9387,18 +9388,22 @@ ins_s_left(void)
     undisplay_dollar();
     if (curwin->w_cursor.lnum > 1 || curwin->w_cursor.col > 0)
     {
-	start_arrow(&curwin->w_cursor);
+	start_arrow_with_change(&curwin->w_cursor, end_change);
+	if (!end_change)
+	    AppendCharToRedobuff(K_S_LEFT);
 	(void)bck_word(1L, FALSE, FALSE);
 	curwin->w_set_curswant = TRUE;
     }
     else
 	vim_beep(BO_CRSR);
+    dont_sync_undo = FALSE;
 }
 
     static void
-ins_right(
+ins_right(void)
-    int	    end_change) /* end undoable change */
 {
+    int end_change = dont_sync_undo == FALSE; // end undoable change
+
 #ifdef FEAT_FOLDING
     if ((fdo_flags & FDO_HOR) && KeyTyped)
 	foldOpenCursor();
@@ -9442,8 +9447,9 @@ ins_right(
 }
 
     static void
-ins_s_right(void)
+ins_s_right()
 {
+    int end_change = dont_sync_undo == FALSE; // end undoable change
 #ifdef FEAT_FOLDING
     if ((fdo_flags & FDO_HOR) && KeyTyped)
 	foldOpenCursor();
@@ -9452,12 +9458,15 @@ ins_s_right(void)
     if (curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count
 	    || gchar_cursor() != NUL)
     {
-	start_arrow(&curwin->w_cursor);
+	start_arrow_with_change(&curwin->w_cursor, end_change);
+	if (!end_change)
+	    AppendCharToRedobuff(K_S_RIGHT);
 	(void)fwd_word(1L, FALSE, 0);
 	curwin->w_set_curswant = TRUE;
     }
     else
 	vim_beep(BO_CRSR);
+    dont_sync_undo = FALSE;
 }
 
     static void

src/testdir/test_mapping.vim

@@ -140,9 +140,32 @@ func Test_map_cursor()
   imapclear
 endfunc
 
+func Test_map_cursor_ctrl_gU()
+  " <c-g>U<cursor> works only within a single line
+  nnoremap c<* *Ncgn<C-r>"<C-G>U<S-Left>
+  call setline(1, ['foo', 'foobar', '', 'foo'])
+  call cursor(1,2)
+  call feedkeys("c<*PREFIX\<esc>.", 'xt')
+  call assert_equal(['PREFIXfoo', 'foobar', '', 'PREFIXfoo'], getline(1,'$'))
+  " break undo manually
+  set ul=1000
+  exe ":norm! uu"
+  call assert_equal(['foo', 'foobar', '', 'foo'], getline(1,'$'))
+
+  " Test that it does not work if the cursor moves to the previous line
+  " 2 times <S-Left> move to the previous line
+  nnoremap c<* *Ncgn<C-r>"<C-G>U<S-Left><C-G>U<S-Left>
+  call setline(1, ['', ' foo', 'foobar', '', 'foo'])
+  call cursor(2,3)
+  call feedkeys("c<*PREFIX\<esc>.", 'xt')
+  call assert_equal(['PREFIXPREFIX', ' foo', 'foobar', '', 'foo'], getline(1,'$'))
+  nmapclear
+endfunc
+
+
 " This isn't actually testing a mapping, but similar use of CTRL-G U as above.
 func Test_break_undo()
-  :set whichwrap=<,>,[,]
+  set whichwrap=<,>,[,]
   call feedkeys("G4o2k", "xt")
   exe ":norm! iTest3: text with a (parenthesis here\<C-G>U\<Right>new line here\<esc>\<up>\<up>."
   call assert_equal('new line here', getline(line('$') - 3))

src/version.c

@@ -775,6 +775,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1055,
 /**/
     1054,
 /**/